The general rule is, if your cold is in your head then you are ok to exercise if you feel up to it and fellow exercisers don't mind you sneezing all over them. However if it goes to your chest then it's best to wait until it's gone. Sometimesa virus can put stress on the heart and if you exercise when suffering, it is possible to cause yourself a few problems (the worst being death!).
SO I'd say wait until you feel better. Who wants a gym buddy who spreads germs anyway? And what quality of workout can you get if you feel that ill? No point going til you're better. So take plenty of zinc and Vit C supplements, rest and start back slowly. It only takes 2 weeks for your fitness level to slump by 50% of what it was, so when you return don't be surprised to find you can't do as much and have to start back slowly. However you will soon be up to speed again !